This invention relates to switchable contact of lightning arresters to power lines on power poles and on or near transformers.
Currently, the most commonly used lightning arresters on power poles and on or near transformers are not designed to continue to operate repeatedly after nearly all lightning strikes, but to be sacrificial with designedly predetermined self-destruction from lightning electrical surges in excess of design amounts which are most typically 10 KV.
After sacrificial self-destruction, the lightning arresters must be replaced promptly at high risk by line workers. The high risk results from not shutting down power lines to a self-destructed lightning arrester while line workers electrically connect a replacement lightning arrester to a power line in order to avoid interruption of electrical service to residential and commercial power users and in order to save high power-plant costs. For initial installation of lightning arresters, power to power lines and transformers can be delayed until the lightning arresters are installed. Shutdown of a power line is expensive and time consuming for single and separate replacement of lightning arresters because (a) high power-plant-employee costs in addition to power-line workers are required and (b) shutdown for a single power line or transformer often requires shutdown of branched power lines to a plurality of users. Accordingly, power-line workers are often under employment pressure to avoid injury-preventive shutdowns for replacing single lightning arresters. Generally, the replacement can be accomplished safely, but serious injury and death of line workers result frequently from unexpected electrical surges and from accidental occurrences during replacement and electrical-line contact of the lightning arresters without safety shutdowns.
There is no known switchable lightning-arrester system for allowing replacement of lightning arresters with safe electrical connection to a power line without interrupting electrical service and without expensive power-plant shutdown of power in a manner taught by this invention.
Examples of most-closely related known but different devices are described in the following patent documents:
U.S. Pat. No.InventorIssue Date2,296,991FoxSep. 29, 19423,614,700Beard, et al.Oct. 19, 19713,497,148MacDonaldAug. 07, 19904,688,013NishikawaAug. 18, 19874,546,341McNaghten, et al.Oct. 08, 19854,795,996Brown, et al.Jan. 03, 19894,814,550NewbergMar. 21, 19894,450,425ManningMay 22, 1984